how to extract(psychonauts 2)

models, textures, images, et cetera

use Umodel/UEviewer for psychonauts2. (direct download link)

you will need to download ordinary uModel first, and move psychonauts' uModel into its folder, to get the required DLLs, etc..
you will also need Blender PSK/PSA import addon if you want to use the models in Blender.
the rest is quite self-explanatory or contained in right-click menus, but there's additional support/documentation on gildor.org if you need it.

audio

use fmodel.
version 4 is fine for audio, but for other things you might need to go back to version 3.
you can find detailed instructions at the bottom of the page, but first i have to include a script by Avis which sorts the audio files for you after conversion(google wem-wav or wem-ogg conversion).
script link.
original instructions by avis:

I've created a python 3 script that scrapes through the json and xml files and moves any unsorted audio data it has info on into their original folders. I also have backups of these files on the drive if you dont have them extracted yourself. there are actually duplicates of files between banks so this also deletes those if they're already in the sorted content folders, so keep that in mind.
I've included batch files but you need to have python 3 installed and in your PATH for those to work. there's 2 versions of the script, choose according to your audio files' extensions, then toss them and all the xml and json files in with your unsorted stuff and just let it run
(oh and this only works on a file if it hasn't been renamed at all so be careful)

glorious. ok, now here's some detailed fmodel instructions:
(NOTE: these instructions will cause a long extraction process that may take several hours, and will create several thousand audio files. make sure you have mastered time & space.)

open fmodel.exe
select "directory" > "selector" and navigate to your psychonauts 2 install
double click the psychonauts 2 pak and wait a second for the list to populate.
navigate to the following directory: Psychonauts2>Content>WwiseAudio>Windows
in the "windows" folder are ~2000 audio files, including music and SFX.
inside that folder is another, "English(US)" which contains all the game dialogue. (~17,000 files)
right click the folder of your choice and select "extract folder's assets". then wait several hours if you selected the dialogue folder.(sorry)
you will need a converter to play the resulting WEM audio files. i recommend this one if you want to convert them to OGG.
it is highly recommended at this point you run Avis' audio sorting script(that one from earlier on this page) which will move audio into nice little manageable folders.

if you are having trouble finding the extracted files, the default output directory will be something like: \FModel[exe location]\Output\Exports\Psychonauts2\Content\WwiseAudio\Windows\English(US)